96 MODERN CLASSIFICATION OF INSECTS. 
provided with a vast number of very minute points, which serve to 
irritate the wound, and to cause an overflowing of the sap; the 
wounds further increase in size, according to the growth of the egg, 
the latter curious circumstance having been discovered by Vallisnieri, 
and also recorded by Reaumur (vol. iii. p.579., and v. p. 121.) ; the 
eggs imbibing nutriment in some unknown manner, through their mem- 
branous skins, from the vegetable juices which surround them, and 
attaining twice their previous size. Sometimes also these attacks are 
succeeded by the production of galls of various kinds, which serve 
for the residence and support of the young larve. In general, how- 
ever, the larve are external feeders ; occasionally, as in the species 
which feed upon the leaves of the turnip and gooseberry, occurring to 
so great an extent, that they are the cause of real injury to the 
farmer and horticulturist. These larve, in their form and colours, as 
well as in the number of prolegs with which they are provided, have 
a very considerable resemblance to those of the Lepidoptera ; in the 
true caterpillars, however, the legs and prolegs do not exceed 16 
in number, whereas the false caterpillars of the Tenthredinide, (with 
a very few exceptions), have from 18 to 22. The prolegs differ from 
those of the Lepidopterous larve, in being simply membranous, and 
destitute of the coronet of curved spines which exist in the latter. 
The body is divided into twelve cylindrical segments, exclusive of the 
head ( fig. 70. 2—9. head and details of Trichiosoma larva) having 
nine pairs of spiracles (fig. 70. 10., head and prothorax of larva of 
Cimbex, to show the prothoracic spiracle). They have only two 
simple eyes (fig. 70.9.) placed at the sides of the head ; the antenne 
are very short and conical (fig. 70. 8.) ; the upper lip is generally 
emarginate in the middle. The mandibles are powerful, horny, and 
more or less toothed ( fig. 70. 3, 4.) ; the maxillee are membranous and 
bilobed, with short, 4-jointed palpi (fig. 70. 5. maxilla in situ, 70. 6. 
ditto, separated), and the labium is small and fleshy, with very short 
conical, 3-jointed labial, palpi (fig. 70. 7.), and provided with a spin- 
naret and silk secretor, but they produce silk in a very small quantity. 
They almost exclusively feed upon the leaves of various trees and 
plants. They have also the habit, especially when alarmed, of rolling 
themselves up in a spiral manner, so that in this position they bear 
avery considerable analogy to the Iulide. Their colours are generally 
green, of various shades, with lines and spots of various colours. 
They shed their skins several (ordinarily four) times, materially 
